Piston



. piston, onewhich, during the reciprocationf- Patented Jan. 6, 1925.

' f p vonrvnnn. Banl'rnnnor nnfrnorr, ivi*ICHIGAN-L`l'` Heron.

f applicationnled :time 4,:

To all 'whom'z't concern. 'f

Be it knownlthat I, OLIVER E. BARTHEI.,

a citizen of the United lStates oflAfmerica,

residing at Detroit, inthe county of Wayne I and State of Michigan, have invented cer-l tain new and useful Improvements in Pis-- tons, of which'the following'is a specification, reference beingha'd thereinv to the ac'` companying drawings. i l

vThis invention relates tora variable length in an 4engine cylinder, may automatically in the operation ofjaninternal combustion Briefly` c le'scrib'ed, ythe piston,v includesl a skirt, somewhat self adjusting relative'v vto.A cylinder walls, articulated with aconnecting j rod. Movable'with the'piston skirt is 'an" inner pistonihead reciprocable in an outerV piston head, which isQadapted to operate with the skirt in lan engine-cylinder.

l or outer piston heads, and the piston asa whole may be used in any typev of internal combustion engine having cylinderslforfrcs ciA rocable pistons. f

y means of this'variable length piston, the exhaust gases are driven entirely out' of the working cycle during theexhaust stroke. Only a. minute part ofthe exhaustfgases remains to dilute andl weaken the charge,

instead of the entire compression spac'efull, as in the c'ommonlyknown Otto cycle. With my mechanism the piston lieadihas three strokesv of' varying length. Starting with the beginning of the suction stroke, the piston is at the extremehead endfof the cylinder, due tothe partial vacuum, ,because of the inertia of the exhaust gas, the inertia of the piston and the lexpansion `of the-air compressed under the fpistonhea'd.'v rl-he spring is compressed and the piston automatically lengthens.A At the end of the suction stroke advantage isagain takenvof the inertia of the piston and incoming lgas which tends to release lthe tension of the spring and cause the piston head to descend,

The outer piston head afordsa normally'closedf i920. seria; No; 386,462.;

thus' shortening the "pis-ton. :and j increasing the volume of thesuction stroke, thereby increasing the volumetric efiiciency considerably over that possible with the Ottoffcycle.

t' During the compression stroke, the compresv slon pressure'.V causes` the piston to shorten by compressing-thevair trapped underthe plston head and also distending the spring 'l to' a predetermined klength governed'by the. volume of the compression space, above :the pistonhead and by the tensionof-tlie spring: in conjunction with the volume ofthe comhave its Alongitudinal dimension increased and decreased to lproduce beneficial lresultsy pression space under thepis'ton head'. "On completlng thecompressionstroke, the pis#k ton-has moved a distance equalto abouttwothirds of the suction stroke,-compressingthe charge into abouton'e-third of its original Y i volume. The charge is thenignited, the ex; Y

plosion drives the `piston forward, in its' shortest form, whichjpositionis maintained until, Aas stated 1n the beginning, the piston returns to the extrem'efend of thecylinder i and lengthens on the way-up due to the inertia of the piston,'rth'e`inertiaof lthe ,ea-A

haust gascolumnland the compr'ess'edi air under the piston head overcoming thel spring, and the frictional resistance-'of the cylinder' walls, fwhich-,permitsthe y.piston head yto travelat a greater vrate thanI thefpiston skirt.

By this arrangementtheincoming charge is materially increased :which increases `the volumetricL eliciency `of the engine and the4 compression space is entirely `clearedof lex#4 haust gases during-the exhaust stroke.' .My invention willA 'be hereinafter-.con-

sideredand then claimed, and reference will now be dhad 'to the drawing, whereinff v Figure ll `is .-a vertical sectional-,viewof l slight.modification in the pistonv and vap-f pliedxto an Lhead type'of. engine,.and`r v- Fig. 4 isja `diagrammatic view showing the comparative length of piston strokes. y

In the drawing the referencel numeral l denotes a portion of an engine cylinder having a water Ajacket 2, an intake valve 3 and l an exhaust Valve 4, 4and these elements are of' a conventional form "common ,to a horlzontal orvertical typeof internal combustion engine.

, always ing ends 9 of parallel arms 10, said arms supporting the inner piston head previously mentioned and now des gnated 11.

This inner piston head has side walls or an annular flange 12 terminating in a feather ork knifeedge which engages the annular 1nterior wall 13 of the outer piston head, designated 14, said outer'piston head telescoping the inner pistonhead 11 and providing anair chamber 15 therebetween. ,The air chamber 15 contains a body of air or fluid that may be compressed and allowed to expand lin the chamber by the outer piston head 14 moving to and .from the inner piston head, the-air' being com ressed inthe chamber kwhen-the inner an outer piston heads are in the position 'shown in Fig. 2. lVith the heads in proximity to each other,

` as shown in this view, the telescoping movel mentofv the outer piston head is limitedby a centralboss 16 of said head engaging the innerfpiston head 11,- and said central. boss has a stem or post 17 extending through a central guide portion 18 of the inner piston` head 11.l On the end of the steml 17 is an abutment 19 and `encircling said stem, between lthe abutment and the central guide portion 18 of the inner piston head 11, is a coiled expansion spring 20 which is held-under compression, as shown in Fig. 1, by the bodyof air within the chamber 15. The central guide portion 18'ofthe inner piston head 11 has feather'edges 22-snugly embracng'thc stem 17, so that the chamber 15 may be positively closed by the inner piston head 11. The compression of` air in the chamber tends to more securely hold the feather edges o'f thepguide 18andthe flange 12 against the piston wall 13 and thus seal the chamber 15. The stem 17 and. the abutment 19 may be conveniently in the form of a bolt and washer or head thereon, and the outer walls ofthe inner and outer piston heads may *be provided with packing rings of'a conventional form.

-It is apparent that the abutment 19 of the outer piston head constitutes means for limiting the movement of the outer piston head, inone direction, relative to the inner piston head, but instead of attaching this abutment to the central portion of the outer piston head I may dispense with the stem the connect- 17 andits appurtenant parts and-'attach an abutment 21 to the inner open end ofthe outer lpiston head, as shown in Fig. 3, the abutment 21 being in the form of a nutor retaining ring screwed or otherwise mounted in the inner end of the outer piston head.

`Considering theoperation ofthe piston, the inner and outer piston heads have a selfadjustment relativev to the skirt 5, which .serves as a cross head, andthis adjustment is one of the important features of my invention, as the piston heads are relieved 4 from any side'thrust by the connecting rod 8 ora pltman andcan readily accommodate themselves to the l*walls of the cylinder. The gap between the inner and outer piston heads and the skirtis also essential', as heatfrom the piston heads can pass into the skirt and be transferred to and absorbed by the cooling agent of the cylinder. 1. ,These featuresalone permitA of therpiston being advantageously used in connection with an air compressor. Y i

. Considering 4the inner and outer piston heads, the normal `relative position of these heads is indicated in .Fig.'1, and ywith the exhaustfvalve 4gopen and-the piston on its exhaustv stroke the outerpiston head 14 will completely scavengethe cylinder; On the exhaust stroke the piston lengthens or the outer head 14 assumes an extended position relative to theinner -head 11 due to the inertia of the pist0n,rthe inertia of the exhaustinggases, and the expansionof air between said piston heads, these three forces cooperating to overcome the expansive force of the spring 20 'and the V,frictional resistance of the cylinder walls.` It is therefore possible for the outerpiston head to travel at-a greater rate of speed than the inner piston head 11 which is connected to they skirt 5 and the latter held by the connecting rod 8.

At the end of the suction stroke, as stated in the beginning, advantage is again taken of the inertia of .thepiston and the incoming charge of gas, which vtends to release the tension ofthe spring and cause lthe outer piston head yto approach the inner piston head, thus shortening the piston and increasing the volumetric eiiiciency of the piston or the capacity of the-cylinder for gasnor an explosive charge. Whenthe piston starts on its compression stroke ythe outer piston head may tendto move in advance of the inner head, due to the expansion kof the body of air within the chamber 15, but as the piston advances, Aon its compression `stroke and the explosive charge is compressed, the body of air between the inner and outer pistonsis compressed, assisted by the expansive force of the spring 20. The compression stroke relative vto the suction andexhaust strokes has been comparatively indicated in F ig. 4 and onthe completion ofthe compression stroke the piston has moved a dlstance equa to approximately two-thirds of the suction stroke, compressing the explosive charge into approximately one-third itsoriginal volume. Assuming that the charge is then ignited, the explosion drives the piston, in its shortest form and such form is maintained until, as heretofore stated, the piston returns to the extreme end of the cylinder and lengthens for the exhaust stroke.

During the above operations the abutments cooperate with the outer piston head in limiting its movement relative to the inner piston head, and the body of air between said piston heads provides a pneumatic cushion e'Hect to absorb shocks or vibrations during the operation of the engine. It is also apparent that my4 construction contributes to the dissipation of heat, precludes excessive expansion and distortion, carbon deposits, and undue Wear on the piston due to inequalities between the piston rod andv the piston. All of this contributes to a higher degree of perfection in connection with an internal combustion engine. While in the drawings there are illustrated the preferred embodiments of my in.

vention, it is to be understood that the structural elements are susceptible to such variations and modifications as fall within the scope of the appended claims.

IVhat I claim is 1. A piston for a cylinder comprising two parts constructively arranged and articulated so that one part has a self adjusting lateral movement and the other part a reciprocable movement at an angle thereto, the parts being in constant spaced relation and aioiding a heat dissipating exit from walls of the cylinder exposed between the piston parts. l

2. In an internal combustion engine having a cylinder, a piston reciprocable in the engine cylinder, said piston being composed of a skirt and a head in spaced relation, the skirt being open from end to end and permitting of heat being dissipated from the -cylinder walls exposed between said skirt and head, and means supporting the head relative to the skirt so that said head may move to and from said skirt.

3. A piston comprising parts adjustable relative to each other and providing a constantly open gap between said parts, one of which is open from end to end, and means axially of the piston parts yieldably connecting said parts.

4. A piston comprising heads one within the other with a body of air therebetween `adapted,to be compressed by one head m0,. .ing towards the other head, and guiding saidouter piston head and co-operatingtherewith in providing a sealed air chamber in which air is compressed by said outei piston head telescoping said inner piston head, means connecting said inner piston head to said skirt, and means carried by said outerpiston head and extending'between the connecting means of said skirt and said inner piston head `to limit the outward movement of said outer piston head relative to said inner piston head.

7. A piston as characterizedin claim 6., wherein said inner piston head has an annular feather edge flange against the walls of said outer piston head.

8. A piston comprisin a skirt, an inner piston head connected tereto and held in spaced relation to said skirt, said inner piston head having a closed end, an outer piston head slidable on said innerpiston head and means` carried by said outer piston head and extending through said inner.,

piston head to limit the sliding of said outer piston head in one direction on said inner piston head, said means including. a spring against the outer face of the closed end of said inner piston head.

9. A piston comprlsing a skirt having open ends, a connecting rod extending into one end of said skirt, arms extending into the other end of' said skirt, means connect- 1n said skirt, an inner head carried by said arms, and an outer head movable on said'inner head.

l0. A piston as in claimv9,fandrmeans bei tween said arms connected to the outer head and aii'ording a yieldable "connection between said heads. l

In testimony whereof I aix my signature in the presence of two witnesses.

OLIVER E. BARTHEL. Witnesses:

KARL H. BUTLER,

ANNA M. Domi.

said arms and said connecting rod to 

